Photoflash lamp



Jan. 16,1945. O w, HOPKINSON, JR., ETAL 2,367,583

PHOTOFLASH LAMP Filed Dec. 50, 1941 fl/NVENTORSJ .W. 0 Inse t 6 R .fuily ATTORN EY Patented Jan. 16, 1945 rno'ror'nasn LAMP Oliver William Hopkinson. In, Newark, and Paul 'Barringer Tully, Bloomfield, N. J., aslignors to Westinghouse Electric dz Manufacturing Company, East Pittsburgh, Pa.,

Pennsylvania a corporation of Application December 30, 1941, Serial No. 424,844

2 Claims.

This invention relates to photo-flash lamps and more particularly to photo-flash lamps having an enclosing radiation permeable envelope comprised of an organic plastic such as cellulose acetate, and of the general character of lamp described in copending application, Serial No. 298,276, filed October 6, 1939, by M. J. Neumann de Margitta, assigned to the same assignee as this application and issued March 24, 1942 as Patent Number 2,227,481.

In the commercial production of a photo-flash lamp of the'type described and claimed in said patent, it is preferable that the lamp structure, per se, be adapted to be assembled and completed with the minimum of manual effort and a maximum of high speed mechanical effort characteristic of modern lamp manufacturing practice.

One of the objects of the present invention is to provide a lamp structure'which is adapted to be assembled and manufactured in accordance with modern high speed lamp manufacturing practices and upon modern high speed lamp manufacturing machinery.

Another object of the present invention is to provide a two-piece envelope comprised of molded cellulose acetate material with previously sealedin leads, the two-piece envelope adapted to be mechanically joined together, hermetically sealed Fig. 'l is a sectional view along plane 1-1 of Fig. 5 illustrating assembly of thelead-in wire with its nipple or associated portion 01' the envelope;

Fig. 8 is an enlarged sectional view illustrating the retention of the base on the envelope and constituting a feature of the present invention.

Referring to the drawing, the photo-flash lamp of the present invention comprises essentially a two-piece envelope E -E'*, each member comprised of radiation permeable molded cellulose at the joint into a lamp assembly and exhausted,

filled with an oxygen atmosphere, sealed from the atmosphere and based in a sequence of automatic mechanical operations characteristic of modern high speed lamp manufacturing equipment.

Still another object is to provide an improved means for sealing-in lead wires through one of the parts of said two piece envelope.

A further object is to provide an improved means for attaching and securing a base to the finished lamp.

Other objects and advantages will be apparent as the invention is more fully hereinafter disclosed.

In accordance with these objects, we have evolved and constructed the improved photo-flash lamp illustrated in the accompanying drawing wherein- Fig. 1 is a side elevational view of the improved photo-flash lamp of the present invention;

Fig. 2 is an enlarged broken-away sectional view along plane 2-2 of Fig. 1, showing improved features of the present invention;

Fig. 3 is a cross-sectional view along plane 3-3 of Fig. 2;

Fig. 4 is an enlarged section along plane 4-4 of Fig. 2 before sealing the nipples on the wires;

acetate or material of like character, joined together in a sealed mechanical interlock joint J,

as more particularly set forth in co-pending ap-.

plication of R. L. Kreidler, Serial No. 393,320, filed May 14, 1941, and assigned to the same asassignee and issued November 9, 1943: as Patent Number 2,333,725. The said envelope encloses from the atmosphere aluminum foil or shreds A and ignition means F and contains an atmosphere of oxygen under pressure, as heretofore provided in the art. According to the present invention a base B is applied in novel manner to the bottom member E of the envelope.

In the assembly indicated in the drawing, the two-piece molded envelope E and E consists of a dome-shaped upper chamber or bulb piece E and a dish-shaped bottom member or press piece E the open ends thereof being adapted to be telescoped together in a mechanical interlocking arrangement such as indicated by annular bead I0 engaging annular groove ii on and in the outer and inner surfaces respectively of parts E and E. A sealing compound (not shown) is preferably included within this interlocking joint, and if so desired another sealing composition I! may be applied at the outside of the joint for additional security of seal.

Prior to seal-Joining members E and E together, part E is filled with the desired amount of aluminum foil or shreds A and ignition means F is secured in position in part E After seal joining parts E and Ill together, the interior of the interior of theenvelope E and E is evacuated, filled with an atmosphere of oxygen under pressure and then is sealed from the atmosphere. It is desirable to have operations performed mechanically and automatically as herefore practiced inhighspeed lamp manufacture on modernlampmaking equipment.

-Thearrangementprovidedonpartli'facili- I tates the obtaininent of this desired result. As

as cylindrical extension R which depends from andiiIreeniYoroedby-aportionoi'saidparti Pinwith and flaring radially from the upper of said neck. said neck also being provided with a bottom wall P forming part oL theQenvelope. Lead-in support wires Wi-W: forignitionmeansl'passthroughthisbottom waliasongen. The provision of this exhaust tube facllitates the manufacture of the device according to modern lamp manufacturing practices and equipment adapted for production of tipless type of lamp.

- e problem of passing lead-in wires WiWs through the plastic material of envelope E -E in a joint sealed to the atmosphere and supporting ignition means 1" within the envelope 1? and I is primarily mechanical in nature as the plastic material comprising the envelope E and 1'." cannot be fusion-welded onto the surface of lead-wires W1 and Ws. This difliculty is overcome in the arrangement shown by providing lead-in support wires WiWs with flattened areas or sections lt- I8' below bottom wall P and extending said wires through and sealing the flattened sections in tubular nipples L1 and In also depending from and integral with said bottom wall. The nipples are intimately applied to the flattened areas. This operation in part may be readily accomplished mechanically. Following pressure molding of nipples L1 and In about the flattened areas il-II' of lead-in wires W1-W= the extending ends C1-C2 of the wires may be heated in an open flame to a temperature which will effect fusion welding of said nipplu to the wire surface, thus forming a hermetically sealed Joint therebetween.

The advantages gained by providing lead wires Wi-W: with flattened areas is indicated in Figs. 4 toinclusive, wherein Fig. 4 shows the wire (W1) illustrated in perspective in Fig. 6, inserted in position in nipple Li with flattened area it the provision of flattened areas Il-ll' on wires Wl-Wi has been found to overcome this dimculty and to provide opposed and relatively wide flattened surface areas against which the molding pressure may be applied. However, in such an arrangement, the plastic material tends to flow around the thinned edges of the flattened wires, substantially as indicated in Fig. 'i to leave somewhat V-shaped passageways which may extend the entire length of the flattened section. We have found that these openings may be effectively sealed following pressure molding by heating the extending flexible conductors -C1-C2 to a temperature which, by conduction there'along to flattened sections il-ll', results in the substantial fusion of the plastic material next adjacent the surface of the flattened areas.

This fusion of 'plastic te metal occurs -very deflnitely at portions of the wires next adjacent and the closing of the V-shaped passageway at disposed adjacent the bottom end of the nipple.

Fig. 5 shows .the relative position of the parts after pressure molding nipple L1 to the flattened area l3; and Fig. I shows the nature of the'pressure molded joint with the edge openings therealong requiring the fusion scaling for effecting complete hermetical closure thereat.

The arrangement shown provides a ready means for sustaining fllament F in desired position within the envelope Il 1? and a ready means for hermetically sealing the lead-in support wires W1 and W: on which said fllament is mounted. In general, 'it is exceedingly difllcult to obtain a tight seal between the plastic material comprising the envelope Il -1i? and the metal comprising thelead-in .support wires W1 and W1, as the seal therebetween must be essentially a pressure union. The cellulose acetate is heated by any convenient means to a temperature at which it is plastic and is then compacted and pressure molded around the flattened wire surface. Hermetic pressure sealing is difficult to obtain with a rounded wire surface. and

present invention that the same may be widely the sides thereof.

It will be noted that the nipple Lil.e as well as tubulation T depend from the bottom of the envelope but are situated in the completed lamp within the base 8. Said base comprises a cylindrical metal shell the lower end of which is closed by a plug it of electrically insulating material, said plug having an electrically conducting metal center insert or contact terminal II in the outer face thereof. The plug and insert are each provided with an opening therethrough for passage of one of the flexible conductors C: into a position where it may be secured by solder or otherwise in said insert It, Furthermore when the base B is put in position on the cylindrical neck portion R, the other conductor C1 is located in the space gap between the side wall of cylindrical portion P and the inner side wall of base B and hooked through a slot i1 so its end may be soldered, as at II, to the outside surface of said base asindicated in Fig. 2.

The base B, thus positioned on cylindrical portion P, is mechanically secured in position by peening the base side walls inwardly at a plurality of points 2| substantially as indicated in the drawing. The center punch or peened indentations 2| are made at parts of the bottom member E which provides relatively thick walls and next the end ofneck R which is reenforced by the flaring portion of said member, and thus obtains a deflnite embedding of the wicked part of metal in the plastic rather than a springing of the plastic. The mechanical attachment of the base B to neck P as thus obtained may be augmented by a cement Joint between the inner surface of the base B and the neck, if desired.

Another advantageous feature of the present invention is the provision of exhaust tube T in press P of section I? of the envelope El -IF. The provision 'of this exhaust tube facilitates the manufacture of the device according to modern lamp manufacturing practices and equipment adapted for the production of the tipless type of incandescent filament lamp.

It is believed apparent from the above description of the improved photo-flash lamp of the modifled without essential departure therefrom and that the invention is applicable in whole or in part to other lamps than photo-flash lamps, and all such modiflcations and adaptations-are nieable envelope comprised of a material of the character of organic plastic having a subst tially radially flaring portion and a hollow cyl ndrically shaped neck the upper end whereof is integral therewith whereby said flaring portion reenforces the neck at the end thereof next the flaring portion, and a base member therefor, said base member comprising a cylindrical m in: shell having an inside diameter approxima I g and at least as large as the outside diameter of the said neck and having a depth substantially greater than the length of said neck, and me" us to secure said base in position over the said I: ck. said means comprising a plurality of inwardly extending pointed areas in the side wall and next the upper end of the said base member mechanically and permanently engaging in corresponding pointed depressed areas in the surface 2. In a lamp provided with a radiation-- permeable envelope comprised of a material of the character of organic plastic having a substantiall radially flaring portion and a cylindrically shaped neck the upper end whereof is integral therewith whereby said flaring portion reenforces the neck at the upper end thereof next the flaring portion, said neck being hollow and having portions oh its side wall thick in a crosssectional plane and portions thereof thin on the same cross-sectional plane, and a base member therefor, said base member comprising a cylindrical metal shield fitting at its sides around said neck, and having a plurality of inwardly extending peen points mechanically and permanently engaging in the said plastic neck at parts thereof where the wall of said neck is thick go and reenforced.

OLIVER WILLIAM HOPKINSON, JR. PAUL BARRINGER TULLY. 

